Gradient architecture of Si containing layer and improved cutting performance of AlCrSiN coated tools

Abstract

Abstract Si-containing, AlCrSiN gradient coatings are promising candidates for use in advanced cutting tools. An investigation was conducted on several such coatings, including their dry sliding friction, dry sliding wear, adhesion strength, and wet milling performance. Three different coatings were deposited by multi-arc ion plating. Scanning and transmission electron microscopy of AlCrSiN gradient coatings revealed changes in their Si contents, grain sizes, and microstructures as a function of depth below the surface. The best AlCrSiN gradient coatings exhibited higher adhesion strength and high hardness (H ~33\u202fGPa) combined with a low elastic modulus (E ~326\u202fGPa) and a high ratio of H3 to E2 (~0.3402\u202fGPa). They also had low friction coefficients and wear rates against alumina counter-bodies under various normal loads. It is proposed that the improved wear resistance of the AlCrSiN gradient coating was due to a decreased probability of peeling. This AlCrSiN gradient coating also possessed the greatest cutting life due to a reduction in the contributions from abrasive and adhesive wear. Based on this work, the cutting performance of coated tools could be improved by the proper design of Si-containing gradient microstructures.